1. Technical Field
The present invention relates to a ceiling hanger for a projector.
2. Related Art
A ceiling hanger for a projector known in the art is positioned on a ceiling or other places to fix a projector thereto. The projector thus fixed connects to various types of cables for connection with an image device, a personal computer, a network or the like. This structure allows the projector to project an image inputted through the cable onto a screen placed on a wall surface, a standing-type screen or others.
This type of ceiling hanger, including the cable, is designed to become inconspicuous so as to meet the demands for inconspicuousness of the ceiling hanger from the market or for other reasons. Therefore, the ceiling hanger is so configured as to allow attachment of the projector as close to the ceiling surface as possible, with the cable wired in the least visible manner from the outside, so as to improve the external appearance.
There is disclosed in JP-A-2005-172935 a fixing device for a video projector, that includes a fix side member attachable to a support body which fixes and supports a video projector, and a main body side member to which the main body of the video projector is attached, and changes the attachment posture of the main body side member with respect to the fix side member by using a posture change mechanism provided between the fix side member and the main body side member before fixing the video projector. The posture change mechanism contains a ball connected and fixed to either the fix side member or the main body member, a pressed member connected and fixed to the other of the fix side member and the main body member, and a pressing member which presses the ball against the pressed member to fix the ball, and further has an operation lever operated to press the pressing member.
There is disclosed in JP-A-2011-13267, a ceiling hanger which includes a first board provided with a pair of guides and a pair of first holding units disposed at the ends of the guides, and a second board which supports a projector and has a first holding member fitted to areas near both the ends of the guides and sliding with respect to the guides in such a manner as to be rotatably supported by the first holding units.
There is disclosed in 2004-347835, a hanger which includes a unit having legs disposed at the left and right front ends of the main body bottom of the unit to control the height of the hanger placed on a table, and a hanger metal fitting which hangs the unit from a ceiling. The hanger metal fitting has insertion portions at the left and right front ends, and support portions at the left and right rear ends. At the time of hanging from a ceiling, the hanger metal fitting is attached to the ceiling, and the legs are inserted into the insertion portions. In this condition, the right and left rear ends of the main body bottom are positioned in such a manner as to be rotatably supported by the support portions, and the depression angle is controlled by adjustment of the legs.
There is disclosed in JP-A-2009-204902, a projector ceiling hanger which includes a ceiling side fixing member attached to a ceiling, a projector side fixing member attached to a projector, a connection member connecting the ceiling side fixing member and the projector side fixing member, and a direction/posture control unit which controls the direction and posture of the projector.
According to the fixing device for a video projector in JP-A-2005-172935 which controls the position of the projector by using the ball, however, fine adjustment of the position is difficult. Moreover, at the time of fixation of the ball using the operation lever after the control, the controlled position easily shifts, in which case a projection image moves accordingly. In the case of the ceiling hanger disclosed in JP-A-2011-13267, three axes of the horizontal direction, the roll direction (left-right direction), and the up-down direction are adjustable. According to this structure, however, the position control of the projector, and the fixation of the projector by fastening screws after the control are both carried out while holding the projector by hand. In this case, time and labor are required for the control, and fine adjustment becomes difficult. According to the hanger disclosed in 2004-347835, the depression angle of the unit is controlled by using the legs for height control. However, this hanger is exclusively used for devices provided with legs for height control, and therefore offers low flexibility. Moreover, this hanger controls only one axis (depression angle), and cannot adjust a larger number of control axes.
Furthermore, the fixing device shown in JP-A-2005-172935 and the ceiling hanger shown in JP-A-2011-13267 do not clarify the storage channel of the cable. In this case, there is a possibility that the whole cable is exposed to the outside in the space between the ceiling (ceiling surface) and the projector. In addition, the components constituting the fixing device or the ceiling hanger are exposed to the outside. Accordingly, the external appearance of the fixing device or the ceiling hanger becomes undesirable when the device is used at home or installed in offices, for example.
The ceiling hanger disclosed in JP-A-2009-204902 has a hollow area inside a pipe-shaped portion of the connection member. The inside of the pipe-shaped portion corresponds to the wiring channel of the cable. However, when the inside diameter of the pipe-shaped portion is decreased for the purpose of reduction of the thickness of the ceiling hanger or for other reasons, insertion of a plurality of cables becomes difficult.
Moreover, according to the ceiling hanger shown in JP-A-2009-204902, the components constituting the ceiling hanger are exposed to the outside similarly to the devices shown in JP-A-2005-172935 and JP-A-2011-13267. Therefore, the external appearance of the ceiling hanger similarly becomes undesirable when the ceiling hanger is used at home or installed in offices. In addition, dust adheres to the components constituting the ceiling hanger when the components are exposed to the outside. In this case, there arises not only the problem of the deteriorated appearance but also the problem of difficult removal of the adhering dust.
Accordingly, such a ceiling hanger has been demanded which can easily and securely achieve fine adjustment of the position (posture) of the projector in the horizontal direction, left-right direction, and up-down direction, can save the space required for attachment and detachment of the projector, and can reduce the thickness of the projector. In addition, such a ceiling hanger capable of improving the external appearance including the cable wiring has also been demanded.